1. Field of the Invention
This invention relates to the manufacture of clean gaseous mixtures comprising H.sub.2 and CO. More particularly, it pertains to the apparatus and related process for cooling and cleaning the hot raw gas stream produced by the partial oxidation of solid carbonaceous fuels and principally comprising H.sub.2, CO, CO.sub.2, H.sub.2 O and containing entrained solid matter and slag.
2. Description of the Prior Art
In the partial oxidation of liquid and solid hydrocarbonaceous fuels with steam and free oxygen to produce gaseous mixtures comprising carbon monoxide and hydrogen, the gases leave the gas generator at a temperature in the range of about 1700.degree. to 3000.degree. F. Depending on the feed and operating conditions, entrained in the gas stream leaving the gas generator are various amounts of molten slag and solid matter such as soot and ash. It is often desirable to reduce the concentration of these entrained materials. For example, by removing solids from the gas stream, one may increase the life of downstream apparatus that is contacted by the gas stream, such as the life of gas coolers and turbines. Solids removal from the synthesis gas will also prevent plugging of catalyst beds. Further, environmentally acceptable gas may be produced.
In coassigned U.S. Pat. No. 2,871,114-Du Bois Eastman, the product gas and slag from the gasification of coal are passed into a slag pot placed directly below the generator. Water is supplied to the slag pot to collect and solidify the slag which drops out of the gas stream. The gas stream leaves the slag pot and is passed into a quench accumulator vessel where the gas is intimately contacted with water and cooled to a temperature in the range of about 300.degree.-600.degree. F. The gas stream leaving the quench tank is saturated with H.sub.2 O. When the raw gas stream leaving a coal fired generator at a temperature above about 1700.degree. F. is introduced directly into a gas cooler, the slag entrained in the gas stream will deposit out on the inside surfaces of the gas cooler and foul the heat exchange surfaces. In U.S. Pat. No. 4,054,424 no means is provided for removal of the slag from the system.
In contrast with the prior art, by the subject invention, the raw synthesis gas is cleaned without quenching in water and is therefore not saturated. It is also cooled to a temperature in the range of about 1200.degree. to 1800.degree. F., and below the initial deformation temperature of the slag. The thermal energy in the gas stream may be recovered at a high temperature level. Further, the solidified slag particles are removed from the system. Fouling of equipment located downstream for recovering energy from the hot gas stream is thereby avoided.